The present invention relates to a method of folding an airbag of an airbag module. The invention also relates to a device for performing this method and to an airbag module having a base plate and an airbag secured to the latter.
In known methods of folding an airbag of an airbag module first the airbag is secured to a base plate, from which it is then stretched out on a folding device into at least one outer tube. The stretched-out airbag located in the outer tube is then folded by a die or piston of the folding device moving into the outer tube. During folding, the airbag is thus laid in a chaotic folding arrangement.
It is known from DE 298 11 042 U1 to displace a die through the base plate into the airbag in order to stretch out the airbag. Introducing a die in this way is only possible with base plates of airbag modules which are not substantially closed in the direction of stretching out the airbag, however.
It is known from U.S. Pat. No. 6,260,330 to stretch out an airbag of an airbag module before it is folded by inflating it in an outer tube. The method step of inflation results in a relatively long cycle time, however, and is moreover only possible if no inflator is pre-mounted on the base plate.
According to the present invention, before the airbag is folded inside an outer tube, a central portion of the airbag remote from the base plate is to be arranged or mounted or secured on or to a holding device of the folding device, and the airbag is subsequently to be stretched out by pulling this secured central portion. The pulling is performed by a movement of the holding device relative to the receiver. During this movement, alternatively, the holding device or the receiver may be moved individually or in combination relative to one another. In contrast to known methods, according to the invention the airbag is not pushed from the inside outwards in the direction of stretching out, but rather it is pulled on its outside with the aid of a holding device. This pulling may be performed in a manner giving a reliable procedure, using a device that can be produced at low cost.